This invention relates to a system and antenna assembly for mobile satellite communication, television, and broadband services in the Mobile Satellite Service (MSS) industry.
Conventional antenna systems incorporate reflectors to concentrate and boost signal strength or incorporate multiple antenna elements such as patch or slot arrays. In some cases multiple horns are used to provide an array of antenna elements. For purposes of this application, a horn, horn antenna or microwave horn is an antenna that consists of a flaring metal waveguide shaped like a horn to direct radio waves in a beam. When multiple antenna elements are used to increase aperture, the signals are summed in waveguide or printed circuit feeds and may include orthomode transducers and or combiners. The aperture is defined as the area, oriented perpendicular to the direction of an incoming radio wave, which would intercept the same amount of power from that wave as is produced by the antenna receiving it. These are subject to performance degradation due to losses in the reflections or connections used to combine and amplify the satellite signal. As a result, the size of the antenna aperture needs to increase to compensate for the accumulated losses.
In an attempt to increase aperture for mobile applications, antennas often are configured in long and narrow shapes which allow for reduced height but require wider sweep. These can be multi-element configurations or low profile dishes. These can be 34 inches wide and as high as 12 inches. When mounted on a vehicle such as an aircraft, these systems result in increased drag and lower fuel efficiency. The aerospace industry, in general, is striving for smaller and smaller antenna arrays. Smaller arrays reduce drag and reduce weight. Reduced drag and weight results is reduced fuel usage, which results in cost savings and increased profit.
There is therefore a need for an improved communications system which provides a compact high efficiency antenna for mobile applications.